Thermal degradation kinetics and pyrolysis GC-MS study of curcumin

Abstract

The objective of this work was to study kinetics of thermal degradation of curcumin in ambient-1023 K range and identify degradation products by GC-MS. No weight loss was observed up to ∼470 K and two major weight losses occurred beyond this. Sixteen degradation products were identified by GC-MS. Pharmacological properties, including LD₅₀, LC₅₀, gastrointestinal absorption, blood-brain barrier permeation and effect on cytochromes, of the products were calculated using standard software. The LD₅₀ values indicated that the degradation products are more toxic than curcumin. All the decomposition products, except 2-methyl-6-(4-methylphenyl)-hept-2-en-4-one, have the potential to cross the blood-brain barrier that can affect brain functions. Twelve of the compounds showed the potential to inhibit the metabolism of xenobiotics and all the compounds appeared to be non-inhibitors of CYP2C9 and CYP3A4 in contrast to curcumin. Thus, this study suggests that the food materials containing curcumin when heated beyond 470 K will produce toxic substances.

Keywords: Curcumin; Isoconversional analysis; Pyrolysis GC–MS; Thermal degradation.